The present invention relates to computer software, and more specifically to client-server computer software.
Where a single repository of data is shared by many users, a client-server architecture may be adopted. Referring now to FIG. 1, four computers 110, 112, 114, 116 arranged using a client-server architecture are illustrated. In a client-server architecture, a server 110 is used to access a data repository storage device 102 that stores the data that is shared among the clients 112, 114, 116. Clients 112, 114, 116 can request the data from the server 110, process data, provide data to the server 110 and change data stored in the storage device 102 attached to the server 110. Users of the client-server system 100 use a client 112, 114 or 116 to communicate with the server 110 to access the shared data stored in the storage device 102. Clients 112, 114, 116 do not have direct access to the data in the storage device 102, but may request that the server 110 perform actions such as performing queries, or adding to, changing or deleting the data stored in the storage device 102 using server commands sent to the server 110.
Each client 112, 114, 116 is coupled to the server 110 by a connection 122, 124 or 126 between the clients 112, 114, 116 and the server 110. Each connection 122, 124, 126 may be physically separate as shown in FIG. 1, or may be shared using a local area network, or LAN. Ports 142, 144, 146 in each of the clients 112, 114, 116 and the associated cabling provide the OSI layers 1-2 connectivity between the ports 132, 134, 136 of the server 110. If the server 110 will communicate with each client 112, 114, 116 over a LAN, a single LAN interface port may physically replace ports 132, 134, 136, and ports 132, 134, 136 are treated as logical ports.
As the user of each client 112, 114 or 116 performs work, the corresponding client 112, 114 or 116 will send commands to the server 110. Each command from a client 112, 114, 116 is processed by the server 110, which next sends to the client 112, 114, 116 a confirmation that the command has been processed. Until this confirmation is received, the client 112, 114, 116 will wait to send additional commands to the server 110. If a task requires two or more commands to be sent to a server 110 by one of the clients 112, 114, 116, two kinds of inefficiencies result.
The first inefficiency is that the client 112, 114, 116 ties up a port 132, 134, 136 on the server 110 longer than may be necessary because it will wait to receive the confirmation from one command before sending a subsequent command. Where ports 132, 134, 136 are shared among multiple clients as described in copending application Ser. No. 08/873,057 and 08/872,529,xe2x80x9dthe delay in releasing the port while waiting for the command confirmation can impact the performance of the other clients which may try to use the port 132, 134, 136.
The second inefficiency is in the processing of the commands by the server 110. The server software in the server 110 may execute commands from multiple clients 112, 114, 116 with a separate server process for each. If there is a delay between the first and second commands from the single client 112, 114 or 116, the server software in the server 110 may execute commands from other clients 112, 114, 116, requiring the server to incur the overhead of switching from process to process, reducing the throughput and performance of the server 110 to a level lower than would be achievable without the overhead.
A system which allows commands from multiple clients to be switched among a single process, such as is described in copending application Ser. No. 08/872,529, can reduce the overhead associated with changing processes when the two clients sending commands share the same process, however, the overhead associated with switching the session associated with the client can cause similar throughput and performance degradation.
It is desirable to shorten the total period of time that a client 112, 114, 116 is required to use a port 132, 134, 136 on a server 110 to submit a multiple-command task, and to reduce the amount of processing overhead required for the server 110 to execute multiple server commands.
In accordance with the present invention, a device such as a client or a controller determines whether a command to be sent by a client will require a response from the server. Commands that will generate no response other than the command confirmation to the client are queued until a command that will produce a server response other than the command confirmation is also ready to be sent to the server. All of these commands are then sent together as a group, and optionally identified as requiring a single group response from the server. The server can provide a single response for the group, reducing the total time the port on the server is required to be in communication with the client. In addition, because all of the commands are available to the server at the same time, they may be executed in the most efficient fashion by the server.